SAFE AIR (Simulation of Air pollution From Emissions Above Inhomogeneous Regions) is an advanced atmospheric pollution dispersion model for calculating concentrations of atmospheric pollutants emitted both continuously or intermittently from point, line, volume and area sources. It adopts an integrated Gaussian puff modeling system. SAFE AIR consists of three main parts: the meteorological pre-processo
WINDS
(Wind-field Interpolation by Non Divergent Schemes) to calculate wind fields, the meteorological pre-processor ABLE (Acquisition of Boundary Layer parameters) to calculate atmospheric parameters and a lagrangian multisource model named P6 (Program Plotting Paths of Pollutant Puffs and Plumes) to calculate pollutant dispersion. SAFE AIR is included in the onlin
Model Documentation System (MDS)
of the European Environment Agency (EEA) and of the Italian Agency for the Protection of the Environmen
(APAT)

History

SAFE AIR is developed, maintained, and distributed by th
Department of Physics
(DIFI) of the

University of Genoa The University of Genoa, known also with the acronym UniGe ( it, Università di Genova), is one of the largest universities in Italy. It is located in the city of Genoa and regional Metropolitan City of Genoa, on the Italian Riviera in the Liguri ...

, Italy. The first version of SAFE AIR was released in 1996. The current version II was released in 2003 and runs both in the Microsoft Windows and

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, an ...

environment. It has a Fortran codebase.

Input data

Topographic data

Orography Orography is the study of the topographic relief of mountains, and can more broadly include hills, and any part of a region's elevated terrain. Orography (also known as ''oreography'', ''orology'' or ''oreology'') falls within the broader discip ...

* Roughness *Displacement level *Land sea mask

Meteorological data

*Ambient temperature *

Wind direction Wind direction is generally reported by the direction from which it originates. For example, a ''north'' or ''northerly'' wind blows from the north to the south. The exceptions are onshore winds (blowing onto the shore from the water) and offsho ...

Wind speed In meteorology, wind speed, or wind flow speed, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature. Wind speed is now commonly measured with an anemometer. Wind speed ...

*Atmospheric stability classes (A through G) *

Atmospheric pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 7 ...

Cloud cover Cloud cover (also known as cloudiness, cloudage, or cloud amount) refers to the fraction of the sky obscured by clouds on average when observed from a particular location. Okta is the usual unit for measurement of the cloud cover. The cloud co ...

Albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...

Source data

*Position *Dimension *Release height of the emission source *Emission discharge rate of primary and secondary pollutants *Volume flow rate of total gas emission *Exit gas temperature *Exit gas speed

Features and capabilities of SAFE AIR

The model includes

algorithm In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...

s which take into account:

downwash In aeronautics, downwash is the change in direction of air deflected by the aerodynamic action of an airfoil, wing, or helicopter rotor blade in motion, as part of the process of producing lift.Crane, Dale: ''Dictionary of Aeronautical Terms, thir ...

effects of nearby buildings within the path of the dispersing pollution plume; effects of complex terrain; effects of coastline locations;

wet deposition In the physics of aerosols, deposition is the process by which aerosol particles collect or deposit themselves on solid surfaces, decreasing the concentration of the particles in the air. It can be divided into two sub-processes: ''dry'' and ''w ...

, gravitational settling and

dry deposition In the physics of aerosols, deposition is the process by which aerosol Particulates, particles collect or deposit themselves on solid surfaces, decreasing the concentration of the particles in the air. It can be divided into two sub-processes: ' ...

; first order chemical reactions; pollution plume rise as a function of distance; averaging time ranging from very short to annual. The system also includes a

meteorological Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not ...

data input preprocessor, named ABLE. The model is capable of simulating passive or buoyant continuous plumes as well as short duration

puff Puff may refer to: Science and technology * Puff, a small quantity of gas or smoke in the air ** Puff, a light gust of wind#Gustiness, wind ** Exhalation ** Inhalation * Puff model, volcanic ash tracking model developed at the University of Alaska ...

releases. It characterizes the

atmospheric turbulence An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

either by the

boundary layer In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary condi ...

depth and the Monin-Obukhov length or by the Pasquill class.

References

*E. Canepa, F. Modesti, and C.F. Ratto (2000) Evaluation of the SAFE_AIR code against air pollution field and laboratory experiments. Atmos. Environ., 34, 4805-4818. * E. Canepa, L. Dallorto, and C.F. Ratto (2000) About the plume rise description in the dispersion code SAFE_AIR. Int. J. Environ. Pollut., 14, 235-245. *E. Canepa and P.J.H. Builtjes (2001) Methodology of model testing and application to dispersion simulation above complex terrain. Int. J. Environ. Pollut., 16, 101-115. *E. Canepa and C.F. Ratto (2003) SAFE_AIR algorithms to simulate the transport of pollutant elements: a model validation exercise and sensitivity analysis. Environ. Model. Software, 18, 365-372. *E. Canepa, F. D’Alberti, F. D’Amati, and G. Triacchini (2007) The GIS-based SafeAirView software for the concentration assessment of radioactive pollutants after an accidental releases. Science Total Environ., 373, 32-42

*M. Cavallaro, E. Canepa, and E. Georgieva (2007) The SAFE_AIR II dispersion model: description and statistical evaluation of its dispersion module against wind tunnel data from area sources. Ecolog. Model., 202, 547-558

External links

SAFE_AIR Version II Release 1.1 User’s Guide

{{Atmospheric, Oceanographic and Climate Models Atmospheric dispersion modeling